Makarova, who has yet to lose a set, won a women’s doubles crown with Elena Vesnina at the French Open earlier this year and teamed with Bruno Soares to win the mixed double crown in Queens last September. Makarova and Vesnina are the second seed in doubles and are into the third round.

The doubles experience — including spending time at net — has improved her game in singles. Against Radwanska, Makarova won 57 percent of points at the net and also 28 winners.

“It really helps in the singles,” Makarova said.

Her singles career seems to be on the upswing, and not just because of her performance over the last week. Makarova reached the quarterfinals at the Australian Open and the third round at Wimbledon this year. Her first career semifinals berth will be on the line against fifth-seeded Li Na in the quarters.

Makarova is particularly happy she’s playing well at the Open, which she said is her favorite major.

“New York is a little bit similar [to] Moscow,” she said. “It never sleeps. I feel really good in Manhattan and New York. It’s really comfortable for me here.”

* A victorious Lleyton Hewitt threw his head back and his arms wide, soaking in the applause from the U.S. Open Grandstand crowd. One half-expected him to channel his inner Maximus and roar, “Are you not entertained?”

Truthfully, yes, we are. The aging Aussie gladiator is as entertaining as he is tough, fighting off the calendar and younger foes. Hewitt continued his surprising run at Flushing Meadows, knocking off Evgeny Donskoy 6-3, 7-6 (5), 3-6, 6-1 yesterday to reach the Round of 16 for the first time since 2006.

“It’s always great coming back to the place where it all started for me, here at the U.S. Open,” said Hewitt, who won the 2001 Open title. “It’s a special place to come back and play.

“I’ve played some of my best tournaments here. I’ve always played well on the American hardcourts, for starters. But the atmosphere as well, it suits my personality. It’s a lot of fun out here always.’’

The 32-year-old — who faces constant questions about his future and how much longer he plans to play — easily could have been fatigued after having to dig deep for a marathon five-set win over Juan Martin del Potro on Friday night. But yesterday, in a match clocked in at 2:55, he was at his best in the final set and steamrolled the 23-year-old Russian.

Hewitt came to net — winning 24 of his 31 attempts — and attacked Donskoy’s backhand. The 102nd-ranked Donskoy played conservatively, but still committed an unsightly 47 unforced errors. Hewitt also served much better against than he had against del Potro.

“I came out aggressive at the start and I played well right at the start to get up that early break,” Hewitt said. “That was sort of the telling point for that first set really. I served a lot better today, as well, hit my spots well.

“I came [to net] in right from the start today. … That’s what I did right from the start just to try to set the tone out there.”

* Top seed Novak Djokovic has diligently worked on his game at the net, and it seems to be paying off. In last night’s 6-0, 6-2, 6-2 victory over Portugal’s Joao Sousa at Ashe, he won 22 of 30 points at the net.

“I am not obviously as comfortable on the net as I am on the baseline, but I’ve been working at it,” he said. “It’s part of my game that I still need to improve. I’m aware of that.”

Djokovic hasn’t looked to have any weakness at the Open, not dropping a set in three matches. The top-ranked Serb will meet Spaniard Marcel Granollers in the fourth round before a possible quarterfinal matchup with Hewitt.

* Though he does a lot of training in Florida, defending champion Andy Murray still had difficulty adjusting to the extremely humid conditions, coming out sluggishly in his match against Germany’s Florian Mayer.

“It was tough conditions,” Murray said following his 7-6 (2), 6-2, 6-2 victory. “It was very, very humid. But [I] started the second set well. Started hitting the ball a little bit cleaner, was more aggressive after that, and finished it well.”

Next up for Murray is Uzbekistan’s Denis Istomin, who prevailed in five sets over 20th-seeded Andreas Seppi of Italy, 6-3, 6-4, 2-6, 3-6, 6-1. The two have played once before, early this year on hard courts in Brisbane, where Murray held off Istomin, 6-4, 7-6 (3).

* The combined attendance for both the day and night sessions was a record 62,794.